The advantage of getting a purebred cat is you know what your getting. Over the years as a bengal community and with the help of science we have learned what we need to test for to avoid these issues. Resposible breeders will do everything they can to provide a healthy bengal kitten to you.
Here are a few things to keep in mind when looking for a breeder:
If a breeder doesn't do these tests you risk getting a cat which will die early or at the very least go blind. If the breeder doesn't want to answer your questions, you should find another breeder. We always say you get what you pay for, price should not be your only consideration. A "cheep bengal" usually means you could end up spending thousands in veterinarian care and testing.